A Tokyo-bound plane out of Los Angeles International Airport headed back to the airfield Tuesday hours after taking off when a mix-up caused the flight crew to believe an unauthorized person was on board.

Airport police had been told to be ready for All Nippon Airways (ANA) Flight 175's return to LAX before it was discovered there was a mix-up that was ultimately straightened out, airport police told reporters.

Model Chrissy Teigen, who was aboard the plane, said on Twitter that the jetliner turned back to LAX four hours into the flight.

"A flying first for me: 4 hours into an 11-hour flight and we are turning around because we have a passenger who isn't supposed to be on this plane. Why... why do we all gotta go back, I do not know," she tweeted.

She continued tweeting about the inconvenience she, her husband John Legend and her fellow passengers faced, as well as the lounge she was taken to. She eventually boarded a new flight early Wednesday morning.

a flying first for me: 4 hours into an 11 hour flight and we are turning around because we have a passenger who isn’t supposed to be on this plane. Why...why do we all gotta go back, I do not know

A U.S. government official with knowledge of the situation told The Associated Press that the incident involved two brothers — one ticketed on ANA and the other on a United Airlines flight leaving about the same time.

The official who spoke on condition of anonymity says both cleared security and had valid boarding passes. ANA and United are codeshare partners.